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Journal ArticleDOI

Photocatalytic CC bond cleavage in ethylene glycol on TiO2: A molecular level picture and the effect of metal nanoparticles

TL;DR: In this article, the authors studied the photocatalytic polyol conversion on pristine TiO 2 and metal nanoparticles (NPs) decorated TiO2 using ethylene glycol (EG) as the model compound.
About: This article is published in Journal of Catalysis.The article was published on 2017-10-01. It has received 15 citations till now. The article focuses on the topics: Bond cleavage & Ethylene glycol.
Citations
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Journal ArticleDOI
TL;DR: This review highlights the recent progress that provides fundamental insights into TiO2 photocatalysis through direct tracking the evolution of single molecule photochemistry onTiO2 single crystal surfaces using a combination of scanning tunneling microscopy (STM) and other surface science techniques.
Abstract: Heterogeneous photocatalysis has been widely applied in various fields, such as photovoltaic cell, solar water splitting, photocatalytic pollutant degradation, and so on. Therefore, the reaction me...

167 citations

Journal ArticleDOI
TL;DR: The state-of-art synthesis of imines via condensation of amines with aldehydes or ketones often uses homogy, which simplifies the experimental setup and increases the chances of successful synthesis of new imines.
Abstract: Imines are important precursors for pharmaceutical, agricultural, and synthetic chemistry. The state-of-art synthesis of imines via condensation of amines with aldehydes or ketones often uses homog...

45 citations

Journal ArticleDOI
TL;DR: This Review summarizes recent advanced photocatalytic systems for value-added chemical production from renewable biomass, with specific attention on the efficient strategies for controlling the generation of key radical intermediates and their subsequent conversion towards desired chemicals.

35 citations

Journal Article
TL;DR: In this article, an efficient photocatalysts of copper nanoparticles on graphene support are successfully developed for controllably catalyzing the coupling reactions of aromatic nitro compounds to the corresponding azoxy or azo compounds under visible-light irradiation.
Abstract: Copper is a low-cost plasmonic metal. Efficient photocatalysts of copper nanoparticles on graphene support are successfully developed for controllably catalyzing the coupling reactions of aromatic nitro compounds to the corresponding azoxy or azo compounds under visible-light irradiation. The coupling of nitrobenzene produces azoxybenzene with a yield of 90 % at 60 °C, but azobenzene with a yield of 96 % at 90 °C. When irradiated with natural sunlight (mean light intensity of 0.044 W cm−2) at about 35 °C, 70 % of the nitrobenzene is converted and 57 % of the product is azobenzene. The electrons of the copper nanoparticles gain the energy of the incident light through a localized surface plasmon resonance effect and photoexcitation of the bound electrons. The excited energetic electrons at the surface of the copper nanoparticles facilitate the cleavage of the NO bonds in the aromatic nitro compounds. Hence, the catalyzed coupling reaction can proceed under light irradiation and moderate conditions. This study provides a green photocatalytic route for the production of azo compounds and highlights a potential application for graphene.

31 citations

Journal ArticleDOI
TL;DR: In this article, the Pd cocatalyst on TiO2 photocatalyst successfully inhibits the formation of toxic methylphenols, thus promoting the complete mineralization of VOC mixtures into CO2 via the harmless benzaldehyde intermediates.
Abstract: Photocatalytic removal of single volatile organic compounds (VOCs) has been widely investigated; however, photodecomposition of VOC mixtures has been rarely addressed, which may bring safety doubts in indoor air purification due to possible formation of harmful compounds. Here we show that in photocatalytic oxidation of formaldehyde–toluene and formaldehyde–xylene mixtures, the introduction of Pd cocatalyst on TiO2 photocatalyst successfully inhibits the formation of toxic methylphenols, thus promoting the complete mineralization of VOC mixtures into CO2 via the harmless benzaldehyde intermediates. Mechanistic analysis reveals that the loading of Pd cocatalyst effectively removes the inherent surface −OH groups of TiO2, which significantly promotes the activation of O2 into radical dotOH radicals. The Pd cocatalyst also directs the radical dotOH radicals to attack the methyl group instead of the aromatic ring for the formation of benzaldehyde and its further oxidation to CO2, thus yielding a better overall photocatalytic performance.

30 citations

References
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Journal ArticleDOI
Ulrike Diebold1
TL;DR: Titanium dioxide is the most investigated single-crystalline system in the surface science of metal oxides, and the literature on rutile (1.1) and anatase surfaces is reviewed in this paper.

7,056 citations

Journal ArticleDOI
TL;DR: A density functional theory-based, high-throughput screening scheme that successfully uses these strategies to identify a new electrocatalyst for the hydrogen evolution reaction (HER), which is found to have a predicted activity comparable to, or even better than, pure Pt, the archetypical HER catalyst.
Abstract: The pace of materials discovery for heterogeneous catalysts and electrocatalysts could, in principle, be accelerated by the development of efficient computational screening methods. This would require an integrated approach, where the catalytic activity and stability of new materials are evaluated and where predictions are benchmarked by careful synthesis and experimental tests. In this contribution, we present a density functional theory-based, high-throughput screening scheme that successfully uses these strategies to identify a new electrocatalyst for the hydrogen evolution reaction (HER). The activity of over 700 binary surface alloys is evaluated theoretically; the stability of each alloy in electrochemical environments is also estimated. BiPt is found to have a predicted activity comparable to, or even better than, pure Pt, the archetypical HER catalyst. This alloy is synthesized and tested experimentally and shows improved HER performance compared with pure Pt, in agreement with the computational screening results.

3,134 citations

Journal ArticleDOI
20 Jan 2006-Science
TL;DR: It is shown that Au/Pd-TiO2 catalysts give very high turnover frequencies (up to 270,000 turnovers per hour) for the oxidation of alcohols, including primary alkyl alcohols and the addition of Au to Pd nanocrystals improved the overall selectivity.
Abstract: The oxidation of alcohols to aldehydes with O2 in place of stoichiometric oxygen donors is a crucial process for the synthesis of fine chemicals. However, the catalysts that have been identified so far are relatively inactive with primary alkyl alcohols. We showed that Au/Pd-TiO2 catalysts give very high turnover frequencies (up to 270,000 turnovers per hour) for the oxidation of alcohols, including primary alkyl alcohols. The addition of Au to Pd nanocrystals improved the overall selectivity and, using scanning transmission electron microscopy combined with x-ray photoelectron spectroscopy, we showed that the Au-Pd nanocrystals were made up of a Au-rich core with a Pd-rich shell, indicating that the Au electronically influences the catalytic properties of Pd.

1,907 citations

Journal ArticleDOI
TL;DR: It is demonstrated, through a combination of state-of-the-art materials simulation techniques and X-ray photoemission experiments, that a type-II, staggered, band alignment of ~ 0.4 eV exists between anatase and rutile with anatase possessing the higher electron affinity, or work function.
Abstract: The most widely used oxide for photocatalytic applications owing to its low cost and high activity is TiO2. The discovery of the photolysis of water on the surface of TiO2 in 19721 launched four decades of intensive research into the underlying chemical and physical processes involved2, 3, 4, 5. Despite much collected evidence, a thoroughly convincing explanation of why mixed-phase samples of anatase and rutile outperform the individual polymorphs has remained elusive6. One long-standing controversy is the energetic alignment of the band edges of the rutile and anatase polymorphs of TiO2 (ref. 7). We demonstrate, through a combination of state-of-the-art materials simulation techniques and X-ray photoemission experiments, that a type-II, staggered, band alignment of ~ 0.4 eV exists between anatase and rutile with anatase possessing the higher electron affinity, or work function. Our results help to explain the robust separation of photoexcited charge carriers between the two phases and highlight a route to improved photocatalysts.

1,839 citations

Journal ArticleDOI
TL;DR: This paper provides a comprehensive review and critical analysis on the different reaction pathways for catalytic conversion of glycerol into commodity chemicals, including selective oxidation, selective hydrogenolysis, selective dehydration, pyrolysis and gasification, steam reforming, thermal reduction into syngas, selective transesterification, selective etherification, oligomerization and polymerization, and conversion of Glycerol carbonate.
Abstract: New opportunities for the conversion of glycerol into value-added chemicals have emerged in recent years as a result of glycerol's unique structure, properties, bioavailability, and renewability. Glycerol is currently produced in large amounts during the transesterification of fatty acids into biodiesel and as such represents a useful by-product. This paper provides a comprehensive review and critical analysis on the different reaction pathways for catalytic conversion of glycerol into commodity chemicals, including selective oxidation, selective hydrogenolysis, selective dehydration, pyrolysis and gasification, steam reforming, thermal reduction into syngas, selective transesterification, selective etherification, oligomerization and polymerization, and conversion of glycerol into glycerol carbonate.

1,455 citations

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